Proportionate automated blending system for aqueous mixtures

ABSTRACT

A proportionate automated blending system for aqueous mixtures has a plurality of liquid additive control modules which each provide a desired amount of additive to a dedicated mixing injector to blend each additive with water to provide a precise mixture of additive and water. The system has the capability, in between blending cycles, of purging the components of the additive control modules with air and water to displace any residue additive which may remain in the control module. The system is controlled by a controller which controls an actuated control valve to achieve the desired flow rate of liquid additive to acquire the desired proportion of liquid additive to water.

BACKGROUND OF THE INVENTION

The present invention generally relates to automated liquid blendingsystems, and more specifically to automated systems which preciselyblend a liquid additive with water as a base liquid to yield a mixturehaving a precise proportion of the liquid additive to water. Oneapplication of the presently described automated blending system is toprovide a precise blend of fertilizers, nutrients, and other additiveswhich are applied to crop through the irrigation system. However, otherapplications for acquiring precisely blended aqueous mixtures arereadily apparent.

The use of automated metering systems to mix one or more liquids withwater to provide a precise liquid mixture has significant advantage,specifically where the liquid mixture is thereafter utilized inscheduled release. For example, it would be desirable to have such asystem for blending liquid nutrients into irrigation water to provide anefficient and cost effective tool for providing nutrition to crops. Itis to be appreciated that the expense of nutrients for large scalefarming operations can be significant, thereby meriting precisionapplication of these substances. Moreover, it is desirable to obtain theoptimum application program, including the application volume, rate, andtiming, to maximize crop quality and yield. It is also desirable tocreate a record of the nutrient program which may be utilized in thefuture for forecasting future nutrient requirements and maximizing theeffectiveness and cost efficiency of future nutrient programs.

It is would also be desirable to have an automated liquid blendingsystem which includes a cleaning cycle which positively displaces theliquid additive from the valving, controls and mixing apparatus. Whenthe blending cycle has been completed, certain liquid additives cansolidify or gum up inside the various components of the blending system,or evaporate inside the components leaving a precipitate or residuewhich might later cause problems with the system. An automated liquidblending system which includes hardware and controls which positivelydisplaces the liquid additive from the system components would preventproblems which may otherwise result from residue left in the components.

SUMMARY OF THE INVENTION

Embodiments of the presently disclosed invention provide a preciselyproportioned liquid mixture which is blended automatically. Embodimentsof the present system may have a plurality of reservoirs for liquidadditives which are blended with water as a base liquid. Each liquidadditive is stored within a liquid additive storage vessel, which mayhave level indicators which provide output to a controller formonitoring liquid level status for each storage vessel. Each liquidadditive has a dedicated control module for that particular additive.

The control module may include an electromechanical valve on eachstorage vessel which allows the release of a particular additive intothe system, a flow meter which measures the volume of additive whichpasses through the control module, and a modulating electromechanicalvalve that controls the flow of additive from the storage vessel into aliquid additive inlet for mixing injector. The control module may alsohave a purge water intake valve and an air intake valve which allow thesequential flow of water and air through the control module, and out themixing injector for purging any additive residue from the control moduleand out the mixing injector.

The mixing injector of the system is a venturi type injector which has awater inlet, a liquid additive inlet, and a mixed liquid discharge.

In controlling the flow of liquid additive from the control module intothe liquid additive inlet of the mixing injector, the actuated controlvalve receives instructions from a controller such that the controlvalve provides a flow rate of liquid additive into the mixing injectorwhich, when blended with water from the water inlet, yields a mixedliquid having a precise proportion of additive to water.

With respect to the blending of fertilizers, nutrients and otheradditives with irrigation water, embodiments of the present inventionprovide a precisely proportioned mixture of fertilizer and/or nutrientswith irrigation water for application to a crop during an irrigationcycle. Such fertilizers may include nitrogen, phosphorous, potassium,micronutrients (specifically boron, chlorine, copper, iron, manganese,molybdenum, nickel and zinc) and other known liquid nutrients. Otheradditives might include herbicides, insecticides and other pesticides.The precise application of these fertilizers, nutrients, herbicides,insecticides and other pesticides to a crop can optimize crop yields andreduce waste of nutrients. Embodiments of the disclosed inventionmaintain a history of nutrient and water usage, including specificsregarding the application which may be utilized for forecasting futurenutrient requirements.

Upon the completion of the application of the mixed liquid (e.g., uponcompletion of an irrigation cycle for crops) the additive lines arepurged with both water and air to clear leftover additive from thecomponents of the additive control module and the mixing injector.

Embodiments of the presently disclosed apparatus may utilize a touchscreen interface with local (WiFi) and long distance (satellite) remoteaccess. Embodiments of the system may mix up a plurality of differentchemicals, where each chemical may be controlled by an identical liquidadditive control module. Each liquid additive control module may be madeup of a variety of controls and sensing units, and may include an airintake valve, a chemical intake valve, a servo-actuator valve analogcontrol line, a servo-actuator valve analog feedback, a magnetic flowmeter, and a chemical level indicator. The air intake, chemical intakeand purge water intake valves are typically operated by relay at 12-24VDC@0.9 W. The servo-actuator valve analog control line typically has a4-20 mA analog output. The servo-actuator valve analog feedbacktypically has a 4-20 mA analog input. The magnetic flow meter may have a4-20 mA analog input. The chemical level indicator may be a SPDT switch.

The system control requires both analog and digital outputs and inputs.The system itself may have a variety of sensing and monitoring devices,including a boost pressure sensor, a mainline pressure sensor, apaddlewheel flow monitor, a pump starter, a pump overload, a variety ofalarms, halts, shutdowns and valve selector sensors. The pressuresensors may have a 4-20 mA analog output, while the alarms and auxiliarycontrols may be operated by relay at 12-24 VDC@0.9 W. The paddlewheelmonitor may be an open collector type operated at 5-24 VDC. Theshutdowns may be a SPDT switch.

Using liquid nitrogen fertilizer as a specific example, an embodiment ofthe system may have a control valve for controlling the release of theliquid nitrogen, a control valve for controlling the flow of purge airinto the nitrogen-related piping, a water control line for controllingthe flow of purge water into the nitrogen-related piping, a low levelsensor on the liquid nitrogen reservoir, an operating level sensor onthe nitrogen reservoir, an actuator position controller, an actuatorposition sensor, and a magnetic flow meter. Similar controls and sensorsmay be applied to the other individual liquid additive reservoirsprovided in the system.

In one embodiment, the system requires 24 valve selector sensors, 10chemical level sensors (duals), 1 reset sensor, 1 system flow ratesensor, and 1 pump overload sensor. An embodiment of the system mayfurther comprise digital controllers providing output for chemical (5total), water (5 total), and air (5 total), and a total of 5 digitalcontrollers providing output for pump, alarm, shutdown, Aux1 and Aux2.An embodiment of the system may further comprise pressure sensors (2)for water intake and blended solution outtake, chemical flow monitors(5), chemical flow control feedback (5) and chemical flow controls (5).

The modulating valves may be ball valves manufactured by Plast-O-MaticValves, where the modulator has 160 steps, a 4-20 MA input, with 2%hysteresis. In order to achieve a proportionate response between theliquid additive flow rate through the control valve and the modulatingvalve, a particular configuration of internal ball may be utilized inthe modulating ball valve. The modulating valve may have an internalball which controls the flow of liquid additive into the liquid additiveinlet. The internal ball may comprise an inlet side and an outlet side,where a flow channel extends from a flow entry on the inlet side to aflow exit on the outlet side. The flow channel expands as it extendsthrough the internal ball from the flow entry to the flow exit. The flowentry may comprise a triangular opening on one side which transitionsacross the side of the ball into an oblong slit. The flow exit maycomprise an oblong oval on the outlet side.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a process and flow diagram for an embodiment of the presentinvention.

FIG. 2 depicts a plurality of liquid additive control modules may beassembled for utilization in an embodiment of the present invention.

FIG. 3 depicts a plurality of liquid additive control modules may beassembled for utilization in an embodiment of the present invention.

FIG. 4 depicts a plot of flow rate vs. actuator position for anembodiment of an actuated ball valve utilized to deliver a liquidadditive to a mixing injector in the present invention.

FIG. 5 depicts an isometric view of an embodiment of a ball which may beutilized in a flow control valve of the present invention.

FIG. 6 shows a top view of the ball of FIG. 5.

FIG. 7 shows an end view of the ball of FIG. 5.

FIG. 8 shows a front view of the ball of FIG. 5.

FIG. 9 depicts a summary window of a touch screen interface which may beused with embodiments of the present invention utilized in providing aprecise dosage of nutrients through an irrigation system.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures, FIG. 1 depicts shows a process and flowdiagram for an embodiment of the present proportionate automatedblending system for aqueous mixtures 10. The system 10 has a watersupply 12 which supplies water to a mixing line 14 and to a flush line16 through pump 80. Total water provided through the water supply 12 maybe measured by flow meter 40, which may have a flow rate range of 0.3 to20 ft/s with an open collector output that outputs 15 Hz per ft/s for anoutput of 4.5 to 300 Hz, with the output directed to controller 30. Thesystem also has an air inlet 18 which is attached to an air purge line20.

Liquid additives 22, such as nitrogen, phosphorous, potassium andmicronutrients, are stored within liquid additive storage vessels 24.Storage vessels 24 may have level indication switches 26 which mayprovide output to controller 30 which may report a real time liquidlevel inside each liquid additive storage vessel 24 and track liquidadditive usage. Liquid additives 22 may be propelled through the system10 by one or more pumps (not shown). Liquid additive 22 enters into aliquid additive control module through additive intake valve 28. Theunit referred to as the “liquid additive control module” may comprisethe additive intake valve 28, an air intake valve 32, a water intakevalve 34, an actuated control valve 36 and a flow meter 38. The liquidadditive control module is isolated from flow back into liquid additivestorage vessels 24 by check valve 40. Additive intake valve 28, airintake valve 32 and water intake valve 34 may be fail close solenoidvalves operating on 24 VDC. Actuated control valve 36 may be motoractuated utilizing 4-20 ma analog input and a 4-20 ma analog outputverification. The inventors herein have found that the actuate controlvalve 36 may be ball valves manufactured by Plast-O-Matic Valves, wherethe actuator has 160 steps, a 4-20 MA input, with 2% hysteresis, whichmay utilize a modified ball 100 as shown in FIGS. 5-8 and as discussedbelow.

A mixing injector 50 receives liquid additive 22 through liquid additiveinlet 52, with the liquid additive passing through a check valve 42.Mixing injector 50 receives water through water inlet 54 which isconnected to mixing line 14. Mixing injector 50 is a venturi injectorsuch as that manufactured by Mazzei Injector Company of Bakersfield,Calif. and as described in U.S. Pat. No. 5,863,128 by A. Mazzei, aninventor herein. Water and liquid additive 22 are mixed inside themixing injector 50 resulting in a mixed liquid which flows out of themixed liquid discharge 56. A plurality of mixer injectors 50 may beutilized in a system 10, where each mixed liquid discharge 56 is tiedinto a family line 60. Family line 60 may have a pressure transmitter 62for measuring and outputting the observed pressure in the line to theprocessor 30. Family line 60 may thereafter distribute the mixed liquidas required for irrigation or other purpose. Pressure transmitter 82downstream of pump 80 provides output of boost pressure to thecontroller 30.

FIGS. 2-3 show a plurality of liquid additive control modules assembledwithin a cabinet 70. Each control module comprises an additive intakevalve 28, an air intake valve 32, an water intake valve 34, an flowmeter 38 and an actuated control valve 36. Each actuated control valve36 is connected to a mixing injector 50. The components of each liquidadditive control module are hydraulically connected together byinterconnecting piping 64.

FIG. 4 depict a plot of flow rate vs. servo-actuator input value showingthat the actuator with the particular ball described herein providesrelatively linear performance. The actual flow tracks with a 2^(nd)order polynomial utilizing the equation:flow=C ₁(−0.0012x ²=0.9x)+C _(o)where:x=C ₂(−0.0092flow²+1.0414flow)=C ³

where the constants are variances from system to system

FIGS. 5-8 depict a ball 100 which may be utilized in actuated controlvalve 36 to provide the performance illustrated in the plot of FIG. 4.As shown in the figures, the ball 100 may have an inlet side 102 and anoutlet side 104. A flow channel 106 extends from a flow entry 108 on theinlet side to a flow exit 110 on the outlet side 104. As shown in thefigures, the flow channel 106 expands as it extends through the ball 100from the flow entry 108 to the flow exit 110. As further shown in thefigures, the flow entry 108 may comprise an triangular opening 112 whichtransitions into an oblong slit 114 as the flow entry spans across theinlet side 102 of the ball 100. The flow exit 110 may comprise an oblongoval 116 which spans across the outlet side 104. Ball 100 furthercomprises an actuator slot 118 for engagement by an actuator.

FIG. 9 depicts a touch screen interface 120 which may be utilized incombination with processor 30 for embodiments of the proportionateautomated blending system 10 which is specifically utilized for mixingfertilizer and nutrients for application to crops with irrigation water.As suggested by FIG. 9, the processor of the system 10 may be utilizedto actively manage, monitor and record the application of the variousnutrients to a crop.

Having thus described the preferred embodiment of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:

The invention claimed is:
 1. A proportionate blending system comprising:a water supply which supplies water to a mixing line; an air inlet; aliquid additive storage vessel; a liquid additive intake valve; a mixinginjector having a water inlet, a liquid additive inlet, and a mixedliquid discharge, wherein the mixing line provides water to the waterinlet and the liquid additive storage vessel provides a liquid additiveto the liquid additive inlet through the liquid additive intake valve,wherein the water and liquid additive are mixed inside the mixerinjector resulting in a mixed liquid which flows out of the mixed liquiddischarge at a predetermined ratio of liquid additive to water; acontrol valve having an actuator wherein the control valve controls theflow of liquid additive into the liquid additive inlet, the controlvalve providing a flow rate of liquid additive into the liquid additiveinlet at a desired proportion of liquid additive to water; a controllerwhich controls the control valve to achieve a desired flow rate ofliquid additive into the liquid additive inlet to achieve the desiredproportion of liquid additive to water; and an air purge line connectedto the air inlet, the air purge line having an air intake valve whichopens and closes upon receiving instructions from the controller, suchthat upon receiving the instructions from the controller a volume of airis released through the control valve, through the liquid additive inletand out the mixed liquid discharge to purge any remaining liquidadditive from the control valve and the mixing injector.
 2. Theproportionate blending system of claim 1 further comprising a waterflush line which receives water from the water supply, the water flushline connected to a water intake valve which opens and closes uponreceiving instructions from the controller, such that upon the waterintake valve receiving the instructions from the controller a volume ofwater is released through the control valve, through the liquid additiveinlet and out the mixed liquid discharge to purge any remaining liquidadditive from the control valve and the mixing injector.
 3. Theproportionate blending system of claim 2 wherein the air intake valveand the water intake valve sequentially open and close upon receivinginstructions from the controller, such that a first volume of air,followed by a first volume of water, followed by a second volume of airare released in sequence through the control valve, through the liquidadditive inlet and out the mixed liquid discharge to purge any remainingliquid additive from the control valve and the mixing injector.
 4. Theproportionate blending system of claim 1 further comprising a flow meterwhich measures a flow rate of the liquid additive provided to the liquidadditive inlet, wherein the flow meter provides output to the controllerreporting the flow rate for a particular time.
 5. The proportionateblending system of claim 1 wherein the liquid additive storage vesselcomprises a level indicator, wherein the level indicator provides outputto the controller of an observed level of liquid nutrient inside theliquid additive storage vessel for a particular time.
 6. Theproportionate blending system of claim 1 wherein the liquid additivecomprises a nutrient for crops wherein the nutrient is at least one ofthe nutrients selected from the group consisting of nitrogen,phosphorous, potassium, micronutrients, herbicides, insecticides andpesticides.